Docs build refactor

Move docs build logic into the `docs` dir and remove from main gruntfile.
Setup site based on https://github.com/andreypopp/react-quickstart. This
creates a express based server which generates files on request's
removing the need for a user to rebuild the static files.
Removed static files (*.html, bundle.js) from repo and git ignored, this
will stop merge conflicts and these files are no longer needed for
general development.